The present invention relates generally to agricultural planters and more specifically to a furrow depth control structure provided for grain drill planting units.
Available furrow depth control structures utilized on narrow row planting implements provide neither accurate gauging nor simple and easy adjustment of the furrow depth.
Accurate seed placement has long been recognized as one important factor in achieving maximum seed germination and early plant emergence. Unless the seed is planted at the depth where moisture is available, germination will not occur without rain or irrigation. Since the depth at which moisture can be found will vary with geographical location, soil type, soil condition and recent weather conditions, accurate furrow depth control and simple and easy adjustment of that control mechanism is required to realize maximum seed germination and early plant emergence.
Improved furrow formation and accurate depth control has recently been provided in the furrow-forming arrangement subject of U.S. Pat. No. 3,499,495 issued Mar. 10, 1970 to W. H. Pust. The Pust structure has further been adapted for commercial use and provided with a quick and simple depth adjusting structure in the Max-Emerge planter manufactured by Deere & Company and subject of U.S. Pat. No. 4,009,668 issued Mar. 1, 1977 to Brass et al. While the Max-Emerge planter has provided depth control for crops planted in widely spaced rows, such control is not available for crops such as soybeans, peas and edible beans which are planted in narrow rows and often utilize a grain drill.
Planter unit width is obviously restricted when narrow row crops are planted, and accordingly depth bands have commonly been provided to control the furrow depth.
While depth band structures provide reasonable depth control in some planting conditions, they fail to work when surface soil is moist since the soil adheres to the bands. Further, the bands fail to provide cleanly cut, well formed and firmed furrows typically formed with the structure available in the Deere Max-Emerge planter. Since the depth bands are generally mounted coaxially with the axes of the disk openers and secured to the disks, the time and effort to substitute bands in order to change the furrow depth can be substantial.